Gaseous electric discharge device



July 23, 1935. J. BRUIJNES ET AL GASEOUS ELECTRIC DISCHARGE DEVICE Filed June 11, 1934 INVENTORSI Johannes Bruijnes Fleter Schouvvstra,

En el, aswim AT ORNEY Bernard van Patented July 23, 1935 UNITED STATES GASEOUS ELECTRIC DISCHARGE DEVICE Johannes Bruijnea,

Pieter Schouwstra,

and

Bernard van Engel, Eindhoven, Netherlands,

assigno poration of New York rs to General Electric Company, a cor- Application June 11, 1934, Serial No. 130,104

In the Netherlands June 24, 1933 3 Claims. (Cl. 176-122) The present invention relates to gaseous electric discharge devices generally and more particularly the invention relates to such devices the gaseous atmosphere of which consists wholly or 5 in part of a metal vapor.

In copending application, Serial Number 671,318, filed May 16, 1933, the inventor being Cornelis B01, an electric discharge lamp device having a gaseous atmosphere therein comprising a metal vapor, such as sodium vapor, and a septurn in the containerv thereof closing off the stem part of the container from the other parts thereof is described. The source of the metal vapor is located in the part of the container enclosing the electrodes and the septum prevents the metal vapor from coming into contact with the stem parts of the containenwhich are the coolest parts of the container during the operation of the device, to avoid condensation of the metal vapor at the stem parts. which would lower the vapor pressure in the device. The stem parts of the container of such a device can be made of a glass nonresistant to chemical attack by the metal vapor but having better sealing qualities with the current leads than does the vapor resistant glass. The formation of any conducting deposits of con-' densed metal between the current leads in the stem part of the container is avoided in a device of this structure. In the device disclosed in the above referred to application the spaces on either I side of the septum are connected by a long, narrow communicating passage so that all parts of the container can be evacuated through asingle exhaust tube'during the manufacture of the device. The travel of the metal vapor along the narrow communicating passage is very slow and the passage is closed by condensed deposits of vaporous material in the cooler stem end thereof after the device has been operating a comparatively short time. Patent Number 1,961,897, grantedJune 5, 1934, to Cornelis 301 discloses a similar gaseous electric discharge device having material reactive with the metal vapor mounted in operative relation to the stem end of the communicating passage to bind any metal or metal vapor which might seep through said passage and thus positively protectthe non-resistant glass stem of the container from attack by the metal vapor during the operation of the device.

The object of the present invention is to improve the structure of gaseous electric discharge devices of the above type. and advantages attaching to the device and to its use and operation will be apparent to those skilled in the art from the following particular Still further objects description thereof and from the appended claims.

In accordance with these objects the new and novel gaseous electric discharge device comprises a plurality of elongated hollow bodies, rectangular in cross section, made of insulating material and extending through the septum in the container of the device. Each of said bodies surrounds a current lead circular in cross section. A plurality of narrow, elongated, communicating passages are thus provided to connect the spaces on either side of the septum and the current leads are closely surrounded by insulating material. The hollow bodies, rectangular in cross section, are grouped together and pass through a single opening in the septum, when desired, which simplifies the manufacture of the device and makes the electrode mount very strong and rigid. The stem part of the container is filled with a material reactive with the metal vapor present in the container of the device to bind any metal vapor which might seep through the communicating passages during the operation of the device and to protect the non-resistant stem parts of the container from chemical attack by the metal vapor. A reactive material having a large effective surface compared to its mass, such as glass wool, is desirable because it is particularly efiective for the purpose contemplated and is easily placed in the stem part of the container during the manufacture of the device.

In the drawing accompanying and formin part of this specification an embodiment of the invention is shown, in which,

Fig. l is a front elevational, partly sectional view of the gaseous electric discharge device, and

Fig. 2 shows a'detail, in section, of the device illustrated in Fig. 1.

Referring to the drawing the new and novel gaseous electric discharge lamp device comprises a container I having an inverted stem 9, III fused thereto, The part of said container I surrounding the electrodes 4 and 5 is closed off from the stem part 9, l thereof by septum 2 made of chrome steel, for example, and the space between the rim of said septum 2 and the wall of said container 1 is sealed by a body 6 consisting of a mixture of talcum and water glass. The electrodes 4 and consist of a pair of anodes 5 of annular shape and a cathode 4 which is electron emitting when heated. Said cathode 4 consists of a coiled metal filament, such as tungsten or nickel filament, coated with electron emitting material, such as barium oxide. Said cathode 4 is viewed end-on in the drawing. The anodes 5 are mounted on opposite sides of said cathode 4 at substantially equal distances therefrom. Said electrodes 4 and 5 are mounted on current leads I and each of said current leads I is surrounded by an elongated, hollow body 8, rectangular in cross section, as shown in Fig. 2, and which consists of insulating material, such as magnesium oxide. Said bodies 8 are grouped together in a, compact bundle and extend through a rectangular opening in said septum 2. The space between the bodies 8 and the opening in said septum 2 is closed by a body of cement, such as a solution of talcum in water glass. The bodies 8 extend from the electrodes 4 and 5 into the space 3 of said container I. The grouping and the rectangular shape of the bodies 8 and the circular shape of -the current leads I is shown in cross section in Fig. 2 of the drawing. It will be noted that a multiplicity of elongated, narrow communicating passages between the leads 1 and the bodies 8 connect the spaces on either side of said septum 2 which makes it possible to evacuate all parts of I the container I through a single exhaust tube during the manufacture of the device.

The space 3 between the septum 2 and the stem 9, I0 is filled with a material I2 reactive with the particular metal present in the upper part of said container I to bind any metal or metal vapor which should seep through the passages between the leads 1 and the bodies 8 during the operation of the device and to protect the stem parts 9 and ill from the metalvapor. After the first few hours of operation of the device the communicating passages should be closed by deposits of condensed material but even if some of said passages remain open the material i2 is sufficient to protect the parts of the container between the septum 2 and the stem part 9 from attack by the metal vapor. It is advantageous that the material i2 have a large surface compared to its mass and glass wool is'excellent for this purpose.

A quantity of vaporizable material, such as sodium, is introduced into the part of the container l enclosing the electrodes 4 and 5 during the manufacture of the device and a starting gas such as neon, is also introduced into said container I. The sodium vaporizes during the operation of the lamp device and the spectrum of the light emitted by the lamp is rich in the characteristic rays of the sodium vapor. When so dium vapor is present in the upper part of said container i lead glass wool is a suitable binding material to place in the space 3 of said container I.

When the gaseous atmosphere consists of, or comprises a diflicultly vaporizable material, such as sodium, it is advantageous to reduce the radiation of heat from the walls of the container of the device to a minimum to obtain an effective metal vapor pressure during the operation of the device. A heat conservator, such as a double .walled jacket having the space between the walls evacuated or filled with a gas having poor heat conductivity characteristics, in which the lamp device is mounted is eifective for this purpose.

The inner wall of that part of said container i surtounding the electrodes 4 and 5 consists of a glass resistant to the chemical efiects of the hot metal vapor present in said container l during the operation of the device. Such glasses are now known in the art as borosilicate glasses.

'I'hese glasses do not seal readily to current leads oi'tungsten,ommonlyusedlnthisart,andfor this reason we prefer to use a glass non-resistant to the chemical effects of the metal vapor, such as sodium vapor, but having better sealing qualities than the resistant glasses for the parts 0 and II of the discharge device. Such sealing glasses contain an appreciable amount of lead and have a different coemcient of expansion than the resistant glasses. For this reason we prefer to fuse the parts I and II toa part II consisting of a glass or a number of glass layers having graded coeflicients of expansion intermediate those of the resistant glass and the sealing glass and fuse said part II to the part of container l consisting of the resistant glass.

While we have shown and described and have pointed out in the annexed claims certain novel features of the invention, it will be understood that various omissions, substitutions and changes in the forms and details of the device illustrated and in its use and operation may be made by those skilled in the art without departing from the broad spirit and scope of the invention.

.What we claim as new and desire to secure by Letters Patent of the United States is:-

1. A gaseous electric discharge device comprising a container, electrodes sealed therein, a gaseous atmosphere therein. comprising a metal vapor, a septum in said container closing oif the part of said container enclosing the electrodes from the stem part of said container, current leads for said electrodes, said leads being sealed into said stern and passing through said septum elongated, hollow bodies of insulating material surrounding said current leads, said leads being circular in cross-section and said bodies being rectangular in cross-section.

2. A gaseous electric discharge device comprising a container, electrodes sealed therein, a gaseous atmosphere therein comprising a metal vapor, a septum in said container closing off the part of said container enclosing the electrodes from the stem part of said container, current leads for said electrodes, said leads being sealed into said stem and passing through said septum, elongated, hollow bodies of insulating material surrounding said current leads, said leads being circular in crow-section and said bodies being rectangulanin cross-section, the space between the stem part of said container and said septum having a material therein reactive with said metal vapor, the surface of said material being large compared to its mass.

3. A gaseous electric discharge device comprising a container, electrodes sealed therein, a gas-- eous atmosphere therein comprising a metal vapor, a septum in said container closing off the part of said container enclosing the electrodes from the stem part of said container, current leads for said electrodes, said leads being sealed into said stem and passing through said septum, elongated, hollow bodies of insulating material surrounding said current leads, said leads being circular in cross-section and said bodies being rectangular in cross-section, said bodies being grouped together and passing through an open-' ing in said septum.

JOHANNES BRUIJNES. PIETER SCHOUWSTRA. BERNARD van ENGEL. 

